Low viscosity imine reactive diluents and coating compositions made therefrom

ABSTRACT

This invention concerns low viscosity aldimine and ketimine reactive diluents having multi-imine functionality, which are useful in automotive refinish coating compositions, including a process for making them and the coatings that contain them.

BACKGROUND OF THE INVENTION

The present invention relates to curable compositions and moreparticularly to low VOC (volatile organic component) ambient temperaturecurable coating compositions containing low viscosity imine reactivediluents, which are especially suited for use in automotive refinishapplications.

Due to increasingly stringent environmental regulations and the demandfor better performance, reactive diluents/oligomers are becoming crucialcomponents in a variety of automotive coating formulations. This isespecially true for high solids coatings. Such products are typicallyenamels because low molecular weight building blocks can be used to formcross-linked networks that provide robust films. The rate of cure istherefore important since the rate of film formation determines autobodyshop throughput and profitability. Certain imines and imine-containingcoating compositions are known. Representative disclosures can be foundin U.S. Pat. No. 5,198,524, U.S. Pat. No. 3,668,183, U.S. Pat. No.4,772,680 and U.S. Pat. No. 5,288,802. None of these publicationsdiscloses the imines of this invention nor coatings that contain themcharacterized by low volatile organic content (VOC), good sprayability,quick cure and hard, solvent-resistant films formed therefrom.

SUMMARY OF THE INVENTION

The present invention is directed to an imine reactive diluent ofFormula I:

wherein

R and R¹ are the same or different, and are independently selected fromthe group consisting of hydrogen, a C₆ to C₅₀, preferably C₆ to C₆ toC₁₄, more preferably C₆ to C₈ aromatic structure, C₁ to C₅₀ alkyl moietyhaving a linear aliphatic, branched aliphatic, or cycloaliphaticstructure. When the alkyl moiety has the cycloaliphatic structure itpreferably includes 6 to 14 carbon atoms, when it has the linear orbranched structure it preferably includes 1 to 10 carbon atoms.

R² and R³ are the same or different, and are selected from the groupconsisting of a C₁ to C₅₀, preferably C₁ to C₁₀, more preferably C₁ toC₅ linear aliphatic, branched aliphatic, and cycloaliphatic structure.When R² and R³ have the cycloaliphatic structure they preferably include6 to 14 carbon atoms, when they have the linear structure theypreferably include 2 to 10 carbon atoms and when they have the branchedstructure they preferably include 3 to 10 carbon atoms.

Y is a residue with a weight average molecular weight up to about100,000, preferably 14 to 100,000, more preferably 14 to 50,000, mostpreferably 28 to 20,000 and having said linear aliphatic, branchedaliphatic, cycloaliphatic, aromatic structure, or a combination thereof;

wherein R¹,R²,R³ and Y are free from a hydrogen bonding group; and

x is an integer of at least 2, preferably 2 to 50, more preferably 2 to10 and most preferably 2 to 4. Preferred imine reactive diluents ofFormula I are those in which R and R¹ are not both isopropyl.

R², R³ or Y of the imine reactive diluent of Formula I may include oneor more heteroatoms, preferably 1 to 3 heteroatoms in R² and R³, andpreferably 1 to 30 in Y. Preferred heteroatoms include O, S, Si and Pbut not N. To achieve good coating solution viscosity, there will be nohydrogen atoms on any of the heteroatoms.

The imine reactive diluent 1 is a ketimine when R and R¹ are nothydrogen and an aldimine when R¹ is not hydrogen.

Some of the preferred imine reactive diluent of Formula I include thefollowing:

Even more preferred imine reactive diluents of Formula I is:

I. A tetraketimine having the formula:

II. A hexaketimine having the formula:

III. An octaketimine having the formula:

The imine reactive diluent of the Formula I is produced by reacting, inthe presence of a Lewis acid catalyst and a reactive solvent, anacrylate group containing organic compound having the formula:

with 1.0 mole of an imine reactant per mole of acrylate groups in thecompound.

The organic compound may be obtained by conventional means, such as byreacting a polyol having the desired number of functionalities with anacryloyl chloride or acrylic acid. Typically, a free radical scavenger,such as monomethyl ether hydroquinone, generally at 50 to 100 ppm of thereaction mixture, is added to prevent undesired polymerization of theresulting acrylate groups.

The imine reactant may be obtained by first dissolving a correspondingamine compound which includes R² and R³ functionalities into an excessamount of a reactive solvent, generally a ketone for producing aketimine reactive diluent and an aldehyde for producing an aldiminereactive diluent. The reactive solvent contains the desired R and R¹functionalities. Some of the preferred ketones include acetone, methylethyl ketone, methyl pentyl ketone and preferably methyl isobutylketone. Some of the preferred aldehydes include propionaldehyde,butyraldehyde and isobutyraldehyde. The dissolved amine compound reactswith the reactive solvent at elevated temperatures to produce the iminereactant of the following formula:

The imine reactant is then reacted with an organic compound having atleast two acrylate groups to produce the imine reactive diluent.Depending upon the functionalities present on the imine reactant and theorganic compound, the reaction is generally carried out at about −10° C.to 100° C., preferably, at about 0° C. to 60° C. and more preferably atabout 15° C. to 35° C. in the presence of an excess amount of thereactive solvent. Typical Lewis catalyst suitably for use in the presentinvention is selected from at least one member of the group consistingof FeCl₃, acidic gamma alumina, Yb(CF₃SO₃)₃, Sc(CF₃SO₃)₃, tetraisopropyltitanate, and La(CF₃SO₃)₃. The amount of catalyst employable in themethod of the present invention generally varies in the range of 0.01 to20, preferably in the range of from 0.1 to 8 and more preferably in therange of from 3 to 7, all in weight percentages based on the weight ofresidue Y in the Formula I above. The applicants unexpectedly discovereda major improvement of the method of the present invention in that itpermits one to produce the imine reactive diluent in the same reactor,without transferring the reaction mixture to any other reactors. Thesingle reactor preparation makes the process simple-to-operate, safe andefficient.

The excess amount of the reactive solvent present in the reactionmixture is adjusted to provide a coating composition containing theimine reactive diluent of the present invention with a desired amount ofVOC.

Specifically, an imine reactant may be obtained by dissolving diethylenetriamine in an excess amount of 4-methyl-2-pentanone reactive solventand then elevating the reaction mixture under reflux to about 142° C.for producing the imine reactant of the following formula:

Alternatively, the foregoing triamine-bisketimine may be obtained fromAir Products of Allentown, Pa. Triamine-bisketimine (imine reactant) isthen reacted in the same reactor, in the presence of a Lewis catalystwith an organic compound of the following formula:

to produce the imine reactive diluent.

The present invention is also directed to a two-pack coating compositioncomprising a component (i) and a component (ii) wherein:

(i) comprises from 10 to 90, preferably 20 to 80 and more preferably 30to 70 weight percent of an oligomer or a polymer having a weight averagemolecular weight not exceeding about 5,000, preferably 100 to 5,000,more preferably 200 to 4,500 and most preferably 300 to 4,000, andfunctionality selected from one or more of acetoacetate, acrylate,isocyanate, epoxide and cyclic carbonate moieties; and

(ii) comprises from 10 to 90, preferably 20 to 80 and more preferably 30to 70 weight percent of an imine reactive diluent having a weightaverage molecular weight from about 100 to 100,000, preferably 200 to100,000, more preferably 250 to 50,000 and most preferably 300 to20,000, and that is substantially free of hydrogen-bonding moieties andcontains at least three imine groups per molecule wherein allpercentages are based on the total weight of said components (i) and(ii).

One example of the imine reactive diluent is of the following formula:

The oligomer or polymer in the component (i) of the coating compositionof the present invention are conventionally produced. A conventionalacrylic polymer or oligomer, a polyester or a structured oligomer orpolymer is reacted with compounds containing the desiredfunctionalities, such as acetoacetate to produce the oligomer or polymerin the component (i). If desired the component (i) coating compositionmay further include a polymeric component (iii) selected from at leastone of a polyacrylate, polyepoxide, polyurethane and polyester, thecomponent having a weight average molecular weight between about 5,000to 100,000, preferably 6,000 to 50,000 and more preferably 7,000 to20,000, and a pendant functionality selected from at least one ofacetoacetate, epoxide, isocyanate, cyclic carbonate, and acrylatemoieties, the functionality comprising about 1 to 90 percent based onthe weight of the monomer; the composition comprising from about 50:1 to2, preferably 40:1 to 1:2, and more preferably 20:1 to 1:2, all byweight of said components (i+ii) to said component (iii). The polymericcomponent (iii) is prepared in a similar manner as to that describedearlier for the oligomer or polymer used in the component (i).

The ratio of ketimine to acetoacetate, epoxide, isocyanate, cycliccarbonate, or acrylate moieties in the foregoing coating composition isin the range 5:1 to 1:5.

The foregoing coating composition preferably includes:

the component (i) comprising from 25 to 75 weight percent of theoligomer or polymer;

the component (ii) comprising from 25 to 75 weight percent of the iminereactive diluent; and

the component (iii) comprising from 1 to 50, preferably 2 to 40 weightpercent of the polyester polyol or polyacrylic polyol.

In the foregoing coating composition the oligomer or polymer of thecomponent (i) is functionalized with acetoacetate moieties;

the imine reactive diluent of the component (ii) is functionalized withketimine moieties; and

the polyester polyol or polyacrylic polyol of the component (iii) isfunctionalized with acetoacetate moieties.

The present invention is also directed to a two-pack coating compositioncomprising a component (i) and a component (ii) wherein:

(i) comprises from 10 to 90 weight percent of an oligomer or a polymerhaving a molecular weight not exceeding about 5,000 and functionalityselected from one or more of acetoacetate, acrylate, isocyanate, epoxideand cyclic carbonate moieties; and

(ii) comprises from 10 to 90 weight percent of an imine reactive diluentof Formula I described earlier.

If desired, The component (i) of the foregoing coating composition mayfurther include the polymeric component (iii) described earlier.

The present invention is also directed to a method of producing acoating on a substrate comprising:

admixing the components (i) and (ii) of the coating compositiondescribed above to form a pot mix;

applying a layer of the pot mix on the substrate;

curing the layer to form the coating.

The inventors unexpectedly found that by including the highly reactiveimine reactive diluents having low viscosity in a low VOC, high solidscoating composition of the present invention, especially in anautomotive refinish application, a layer from a pot mix of thecontaining composition can be readily applied by conventional means.Moreover, the layer dries at a very rapid rate, which is very importantin an automotive, refinish environment.

Aldimine and ketimine reactive diluents having multi-imine functionalityare disclosed. These highly reactive compositions are furthercharacterized as having substantially no hydrogen bonding sites that cancause an undesirable increase in solution viscosities when employed ascomponents of coating compositions. The imine reactive diluents of thisinvention (ketimines and aldimines) are characterized by the absence ofhydrogen atoms on the nitrogen or oxygen atoms, which contributes tomaintenance of good coating viscosities.

DETAILS OF THE INVENTION

As used herein:

“Two-pack coating composition” means a thermosetting compositioncomprising two components that are stored in separate containers, whichare typically sealed for increasing the shelf life of the components ofthe coating composition. The components are mixed just prior to use toform a pot mix, which has a limited pot life, typically a few minutes,such as 15 minutes to 45 minutes to a few hours, such as 2 hours to 6hours. The pot mix is applied as a layer of desired thickness on asubstrate surface, such as an autobody. After application, the layerdries and cures to form a coating on the substrate surface havingdesired coating properties, such as solvent resistance.

“Low VOC coating composition” means a coating composition that is lessthan about 0.6 kilogram of organic solvent per liter (5 pounds pergallon) of the composition, as determined under the procedure providedin ASTM D3960. The amount of organic solvent used in the presentinvention results in the composition having a VOC of less than 0.6kilogram (5 pounds per gallon) and preferably in the range of 0.012kilogram to 0.528 kilogram (0.1 pounds to 4.4 pounds per gallon), morepreferably in the range of from 0. 12 kilogram to 0.42 kilogram (1.0 to3.5 pounds per gallon) of organic solvent per liter of the composition.

“High solids composition” means a coating composition having a solidscomponent of above 30 percent, preferably in the range of from 40 to 95percent and more preferably in the range of from 45 to 80 percent, allin weight percentages based on the total weight of the composition.

“GPC weight average molecular weight” means a weight average molecularweight measured by utilizing gel permeation chromatography. A highperformance liquid chromatograph (HPLC) supplied by Hewlett-Packard,Palo Alto, Calif. was used. Unless stated otherwise, the liquid phaseused was tetrahydrofurane and the standard was polymethyl methacrylate.“Polymer Solids”, “Binder solids” or “Oligomer solids” means a polymeror binder or oligomer in its dry state.

“Structured oligomer or polymer” means a structured molecule, such as amacromolecule, oligomer or polymer, which unlike conventional resins,has a very well defined structure, such as star, expanded star,dendritic (hyper branched), or cyclodextrinic structured molecules.

“Hydrogen bonding group” means a group containing a heteroatom that isbonded to a hydrogen atom. For example, O, S or N.

“Residue” means a fragment that is a compound, oligomer or a polymer.

Imine Reactive Diluents

Representative imine reactive diluents of this invention are typicallyadvantageously prepared in a single reactor by the following procedure.A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Argon (Ar) inlet andoutlet is charged with a triamine (0.50 mol) having two primary aminetermini and an internal, aliphatic secondary amine group, and analdehyde or ketone (1.22 mol) suitable for use in an imine-formingreaction. The solution is heated to reflux under Ar and water is removedazeotropically via the Dean-Stark trap. The mixture is cooled to roomtemperature and a reagent containing two, three or more acrylate groupsis then added to the reaction flask wherein bis-ketimine to acrylate isabout 1:1 by moles. The resulting mixture is stirred under Ar in thepresence of a Lewis acid catalyst until residual acrylate in thereaction mixture is no longer detectable by ¹H NMR spectroscopy. Theproduct is then filtered under Ar to remove the catalyst.

Coatings

As referred earlier, the preferred coating compositions comprise from 25to 75 weight percent of component (i), from 25 to 75 weight percent ofcomponent (ii), and 0 weight percent of component (iii), based on atotal of 100 weight percent. Other preferred compositions have similaramounts of components (i) and (ii) but component (iii) will be presentat 1 to 50, more preferably 2 to 40 weight percent. Specific preferredoligomers (i) are structured and unstructured polyesters andpolyacrylics that contain pendant acetoacetate or acrylate moieties;preferred oligomers (ii) are of Formula 1 (wherein x=2, 3 or 4); andpreferred polymeric components (iii) are polyesters and polyacrylicsthat contain acetoacetate or acrylate pendant moieties.

Representative coatings containing imines of this invention aregenerally prepared by combining the imines with complementarycoating-formation ingredients that will be obvious to one havingordinary skill in this art.

The imine reactive diluents of this invention provide the followingadvantages over conventional materials:

(i) they are formed from unhindered amines, therefore reactive amine endgroups are generated after unblocking (loss of ketone or aldehyde). Thisresults in rapid reaction with electrophiles;

(ii) they are multifunctional (3 or more). This makes them orders ofmagnitude higher in reactivity than difunctional compounds; and

(iii) they do not contain H-bonding moieties and, as a result, providedramatically lower solution viscosities at high solids (e.g., ≧65percent wt. solids) and can be applied via conventional spray guns. Thisattribute is particularly important for low VOC coatings.

These imine reactive diluents contain all three of the attributesdescribed above, while conventional imines are either difunctional anddo not contain H-bonding moieties, which results in very slow reactionwith electrophiles, or they are multifunctional but contain H-bondingmoieties which precludes their use in high solids, low VOC coatings dueto their high solution viscosities. The compositions of this inventionare characterized by being quick-drying, having low solution viscosity,and cured films made from them have good solvent resistance.

The coating composition of the present invention may also containconventional additives, such as pigments, stabilizers, rheology controlagents, flow agents, toughening agents and fillers. Such additionaladditives will, of course, depend on the intended use of the coatingcomposition. Fillers, pigments, and other additives that would adverselyeffect the clarity of the cured coating will not be included if thecomposition is intended to be used as a clear coating. The foregoingadditives may be added to either the component (i) or the component(ii), or both, depending upon the intended use of the coatingcomposition.

EXAMPLES, COMPARISONS AND PREPARATIONS

Persoz hardness values for the following Examples and Comparisons arepresented in Table 1.

Preparation 1

Diacetoacetate A

The following was added to a glass reactor equipped with a thermometer,stirrer, nitrogen blanket, vigreux column, condenser, distillationadapter and receiver:

Ingredient Parts By Weight ethoxylated Bisphenol A (SynFac 8024; 100Sartomer Chemical) tert-butylacetoacetate  88

The mixture was heated to reflux and 41.2 parts of tert-butyl alcoholwere removed by distillation (the maximum batch temperature was 180° C).The batch was cooled and had the following properties:

Solids =98.81%; Gardner-Holdt viscosity =Z2+½.

Preparation 2

Tetracetoacetate B

The following was added to a glass reactor equipped with a thermometer,stirrer, nitrogen blanket, vigreux column, condenser, distillationadapter and receiver:

Ingredient Parts By Weight pentaerythritol 100 tert-butylacetoacetate464.7

These ingredients were heated to boiling and 217.6 parts of tert-butylalcohol were removed by atmospheric distillation (the maximum batchtemperature was 180° C.). The batch was cooled and had the followingproperties: The solids was 97.18%; the Gardner-Holdt viscosity =Q+½.

Preparation 3

Synthesis of Polyester (AcAc) C

The following materials were charged to a 5 liter reactor equipped with10″ packed separation column, water separator and condenser while beingpurged with nitrogen; 946.1 parts neopentyl glycol, 270.4 partstrimethylol propane, 787.1 parts isophthalic acid, 701.75 parts ofo-phthalic anhydride, 0.7 parts hydrated monobutyl tin oxide, 100 partswater and 83.68 parts toluene. The mixture was heated slowly over 9.5hours to 230° C. while distilling 356 g water (theoretical 356.06 g).The temperature was reduced to 75° C. and 966.32 parts xylene and 817.24g TBAA were added. The temperature was then increased to 140° C. andstirred for 3 hours while removing 404 g liquid (theoretical 382.76).The mixture was then cooled to room temperature.

Preparation 4

Synthesis of Polyacrylic (AcAc) D

To a reactor 273.34 parts butyl acetate were charged and heated toboiling (ca. 125° C.) under nitrogen atmosphere. Subsequently a mixtureof 160.92 parts styrene, 201.1 parts acetoacetoxyethyl methacrylate,40.2 parts hydroxyethyl acrylate, and 27 parts butyl acetate were addedover a period of 210 minutes. At the same time, 21.5 parts t-butylperoxyacetate in mineral spirits (75% solids), and 71.87 parts butyl acetatewere added over a period of 270 minutes. The reaction mixture was heldan additional 60 minutes at boiling after the feeds were complete. Afterthe hold period, an additional 30 parts butyl acetate was added and themixture cooled to room temperature.

Functionalized Oligomers (i) and Polymers (iii)

Polyester (AcAc) (contains pendant AcAc groups) C(iii) Polyacrylic(AcAc) (contains pendant AcAc groups) D(iii) Pentaerythritoltetraacrylate E(i) Epoxide = Epon 1001 (diepoxide oligomer frombisphenol A and epichlorohydrin) F(i) Isocyanate = Tolonate HDT(oligomer from hexamethylene diisocyanate) G(i)

Ketimine Oligomers (ii)

The following oligomers and polymers are employed in the Comparisons andExamples which follow:

Comparison 1a

A coating composition was prepared by successively mixing 15.6 parts ofdiacetoacetate A, 12.7 parts diketimine from isophorone diamine andmethylisobutyl ketone (MIBK) (bisketimine A), 24.5 parts butyl acetate,15 parts xylenes and 2.3 parts methylisobutyl ketone. The resultingmixture was applied to a cold-rolled steel panel via a doctor blade togive a coating thickness of approximately 40 μm after drying.

Comparison 1b

A coating composition was prepared by successively mixing 15.6 parts ofdiacetoacetate A, 27 parts trisketimine prepared from 1 moldimethylmaleate, 3 moles of isophorone diamine and 3 moles MIBK(trisketimine B; applied as a 78% solids in MIBK), 28.2 parts butylacetate, 18 parts xylenes and 2.3 parts MIBK. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 40 μm after drying.

Comparison 1c

A coating composition was prepared by successively mixing 15.6 parts ofdiacetoacetate A, 32.8 parts tetraketimine prepared from 1 mol of thediglycidyl ether of Bisphenol A and 2 moles of the bisketimine ofdiethylene triamine (tetraketimine C; applied as a 55% solids solution),19.9 parts butyl acetate, 13 parts xylenes and 2.3 parts MIBK. Theresulting mixture was applied to a cold-rolled steel panel via a doctorblade to give a coating thickness of approximately 40 μm after drying.

Example 1

A coating composition was prepared by successively mixing 15.6 parts ofdiacetoacetate A, 30 parts tetraketimine prepared from 1 mol of a 1,6hexanediol diacrylate and 2 moles of the bisketimine of diethylenetriamine (tetraketimine D1; 70% solids in MIBK), 22 parts butyl acetate,14 parts xylenes and 2.3 parts methylisobutyl ketone. The resultingmixture was applied to a cold-rolled steel panel via a doctor blade togive a coating thickness of approximately 40 μm after drying.

Comparison 2a

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 18 parts diketimine from isophorone diamine andmethylisobutyl ketone (MIBK) (bisketimine A), 24.2 parts butyl acetate,15.3 parts xylenes and 2.3 parts methylisobutyl ketone. The resultingmixture was applied to a cold-rolled steel panel via a doctor blade togive a coating thickness of approximately 40 μm after drying.

Comparison 2b

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 39.5 parts trisketimine prepared from 1 moldimethylmaleate, 3 moles of isophorone diamine and 3 moles MIBK(trisketimine B; applied as a 78% solids in MIBK), 30 parts butylacetate, 20 parts xylenes and 2.3 parts MIBK. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 40 μm after drying.

Comparison 2c

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 47.9 parts tetraketimine prepared from 1 mol of thediglycidyl ether of Bisphenol A and 2 moles of the bisketimine ofdiethylene triamine (tetraketimine C; applied as a 55% solids solution),18 parts butyl acetate, 12 parts xylenes and 2.3 parts MIBK. Theresulting mixture was applied to a cold-rolled steel panel via a doctorblade to give a coating thickness of approximately 40 μm after drying.

Comparison 2d

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 48.5 parts tetraketimine prepared from 1 molpentaerythritol tetraacrylate, 4 moles isophorone diamine and 4 molesMIBK (tetraketimine E), 18 parts butyl acetate, 12 parts xylenes and 2.3parts methylisobutyl ketone. The resulting mixture was applied to acold-rolled steel panel via a doctor blade to give a coating thicknessof approximately 40 μm after drying.

Example 2

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 30 parts tetraketimine prepared from 1 mol of a 1,6hexanediol diacrylate and 2 moles of the bisketimine of diethylenetriamine (tetraketimine D1, 70% solids in MIBK), 21 parts butyl acetate,14 parts xylenes and 2.3 parts methylisobutyl ketone. The resultingmixture was applied to a cold-rolled steel panel via a doctor blade togive a coating thickness of approximately 40 μm after drying.

Example 3

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 28.9 parts tetraketimine prepared from 1 mol of atrimethanol propane triacrylate and 3 moles of the bisketmine ofdiethylenetriamine (hexaketimine D2; 70% solids in MIBK), 20.4 partsbutylacetate, 14 parts xylenes and 2.3 parts methylisobutyl ketone. Theresulting mixture was applied to a cold-rolled steel panel via a doctorblade to give a coating thickness of approximately 40 μm after drying.

Example 4

A coating composition was prepared by successively mixing 10.3 parts oftetraacetoacetate B, 28.0 parts octaketimine prepared from 1 mol ofpentaerythritol tetraacrylate and 4 moles of the bisketmine ofdiethylenetriamine (octaketimine D3; 70% solids in MIBK), 20.4 partsbutylacetate, 13 parts xylenes and 2.3 parts methylisobutyl ketone. Theresulting mixture was applied to a cold-rolled steel panel via a doctorblade to give a coating thickness of approximately 40 μm after drying.

Example 5

A coating composition was prepared by successively mixing 4.8 parts oftetraacetoacetate B, 6.3 parts polyester(AcAc) C, 18.7 partstetraketimine prepared from 1 mol of 1,6-hexanediol diacrylate and 2moles of the bisketmine of diethylene triamine (tetraketimine D1; 70%solids in MIBK) and 15.2 parts butyl acetate. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 40 μm after drying.

Example 6

A coating composition was prepared by successively mixing 4.8 parts oftetraacetoacetate B, 11.8 parts polyacrylate (AcAc) D, 18.7 partstetraketimine prepared from 1 mol of 1,6-hexanediol diacrylate and 2moles of the bisketmine of diethylene triamine (tetraketimine D1; 70%solids in MIBK) and 11.9 parts butyl acetate. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 40 μm after drying.

Example 7

A coating composition was prepared by successively mixing 2.1 parts oftetraacetoacetate B, 8.1 parts Epon 1001 (Shell), 6.3 partstetraketimine prepared from 1 mol of 1,6-hexanediol diacrylate and 2moles of the bisketmine of diethylene triamine (tetraketimine D1; 70%solids in MIBK) and 8.53 parts butyl acetate. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 40 μm after drying.

Example 8

A coating composition was prepared by successively mixing 3.25 parts ofpentaerythritol tetraacrylate E (Sarotmer SR295), 6.3 partspolyester(AcAc) C,18.7 parts tetraketimine prepared from 1 mol of1,6-hexanediol diacrylate and 2 moles of the bisketmine of diethylenetriamine (tetraketimine D1; 70% solids in MIBK) and 14.2 parts butylacetate. The resulting mixture was applied to a cold-rolled steel panelvia a doctor blade to give a coating thickness of approximately 40 μmafter drying.

Example 9

A coating composition was prepared by successively mixing 3.25 parts ofpentaerythritol tetraacrylate E (Sartomer SR295), 11.8 partspolyacrylate (AcAc)D, 18.7 parts tetraketimine prepared from 1 mol of1,6-hexanedioldiacrylate and 2 moles of the bisketmine of diethylenetriamine (tetraketimine D1; 70% solids in MIBK) and 10.9 parts butylacetate. The resulting mixture was applied to a cold-rolled steel panelvia a doctor blade to give a coating thickness of approximately 40 μmafter drying.

Example 10

A coating composition was prepared by successively mixing 5.86 parts oftetraacetoacetate B, 1.42 parts Isocyanate G(TolonateHDT;Rhone-Poulenc), 10.1 parts tetraketimine prepared from 1 mol of1,6-hexanediol diacrylate and 2 moles of the bisketmine of diethylenetriamine (tetraketimine D1; 70% solids in MIBK) and 11 parts butylacetate. The resulting mixture was applied to a cold-rolled steel panelvia a doctor blade to give a coating thickness of approximately 40 μmafter drying.

Example 11

A coating composition was prepared by successively mixing 3.3 parts oftetraacetoacetate B, 16.8 parts isocyanate G (Tolonate HDT;Rhone-Poulenc),13.2 parts bisketimine prepared from isophorone diamineand 2 moles of MIBK (bisketimine A; 100% solids), 2.4 partstetraketimine prepared from 1 mol of 1,6-hexanediol diacrylate and 2moles of the bisketmine of diethylene triamine (tetraketimine D1; 70%solids in MIBK) and 11 parts butyl acetate. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 40 μm after drying.

Example 12

A coating composition was prepared by successively mixing 12.4 parts oftetraacetoacetate B, 20 parts triketimine prepared from 1 mol oftris(aminoethyl) amine and 3.9 moles of MIBK (Triketimine D4; n=2; 90.4%solids in MIBK) and 21.7 parts butyl acetate. The resulting mixture wasapplied to a cold-rolled steel panel via a doctor blade to give acoating thickness of approximately 58 μm after drying.

Example 13

A coating composition was prepared by successively mixing 10.2 parts oftetraacetoacetate B, 42 parts polyacrylate(AcAc) D, 20 parts triketimineprepared from 1 mol of tris(aminoethyl) amine and 3.9 moles of MIBK(Triketimine D4; n=2; 90.4% solids in MIBK) and 12.6 parts butylacetate. The resulting mixture was applied to a cold-rolled steel panelvia a doctor blade to give a coating thickness of approximately 58 μumafter drying.

Tables 1-3 summarize the reaction of a number of ketimine functionalizedcompounds (ii; A-C, D1-D4 and E) with various oligomers and/or polymers(i and iii; A-G) that contain the appropriate complementary functionalgroup(s) (e.g., acetoacetate, acrylate, epoxide and isocyanate). Thereaction rates to form cross-linked films are monitored by measuringfilm hardness versus time using a Persoz instrument. Persoz hardnessvalues obtained for films that have cured for 3 hours are shown.

Table 1 illustrates the importance of the degree of ketiminefunctionality in determining cure rate, where higher functionality leadsto more rapid cure. For example, if the acetoacetate building block isheld constant by using difunctional acetoacetate A, than the cure rateincreases with increasing ketimine functionality as shown [(Example 1)and (Comparison 1c)>(Comparison 1b) and (Comparison 1a)]. In addition,the importance of hydrogen bonding moieties is also shown, since onlyketimine D1 of our invention shows acceptable cure rate and does nothave hydrogen bonding moieties. Hydrogen bonding moieties dramaticallyincrease solution viscosity in high solids coatings formulations (>about60 to 70% solids).

TABLE 1 Acetoacetate H-Bonding Persoz Example or Ketimine and andMoieties in Hardness Comparison Functionality Functionality Ketimine (T= 3 h) Comparison A A No Tacky 1a (Difunctional) (Difunctional)Comparison B A Yes* Tacky 1b (Trifunctional) (Difunctional) Comparison CA Yes* 38 1c (Tetra- (Difunctional) functional) Example 1 D1 A No 29(Tetra- (Difunctional) functional) *Viscosity is too high to use in highsolids coatings compositions (>60 to 70% solids)

Table 2 shows additional examples of this phenomenon. In this case, atetrafunctional acetoacetate diluent B is used instead of difunctionalacetoacetate diluent A. It is clear that Comparison 2a yields a filmthat cures very slowly because the resulting film is still “tacky” after3 hours cure. For lower molecular weight building blocks such as thoseof the present invention, cure via the formation of covalent bonds isneeded to prepare robust films. This behavior is attributable to theketimine being only difunctional. Comparisons 2b, 2c, 2d provide filmsthat cure significantly faster because the ketimines are tri ortetrafunctional, however, the presence of hydrogen bonding moietiesleads to very high solution viscosities as shown by the #2 Zahn readingsat T=0, 30 and 60 minutes. Again, only examples of the invention hereinprovide rapid cure and low solution viscosities as is shown in examples2-4. The difference in solution viscosity of examples 2, 3 and 4 versusComparisons 2b, 2c, 2d is attributable to the lack of hydrogen bondingmoieties.

TABLE 2 #2 Zahn Readings at Example or Ketimine and Acetoacetate andH-Bonding Moieties Persoz Hardness (T- 77% solids ComparisonFunctionality Functionality in Ketimine 3h) (s-seconds) Comparison 2a A(Difunctional) B (Tetrafunctional) No Tacky T = 0; 18s T = 30 min; 18s T− 60 min; 18s Comparison 2b B (Trifunctional) B (Tetrafunctional) Yes*22 T = 0; >60s T = 20 min; >60s T = 60 min; >60s Comparison 2c C(Tetrafunctional) B (Tetrafunctional) Yes* 76 T = 0; >60s T = 30min; >60s T = 60 min; >60s Comparison 2d E (Tetrafunctional) B(Tetrafunctional) Yes* 10 T = 0; >60s T = 30 min; >60s T = 60 min; >60sExample 2 D1 (Tetrafunctional) B (Tetrafunctional) No 50 T = 0; 25s T =30 min; 28s T = 60 min; 28s Example 3 D2 (Hexafunctional) B(Tetrafunctional) No 68 Example 4 D3 (Octafunctional) B(Tetrafunctional) No 133  *Viscosity is too high

Table 3 illustrates the wide variety of acetoacetate, acrylate, epoxideand functionalized building blocks that can also be reacted with the newketimine(s) to form robust thermoset coatings.

TABLE 3 H- Bonding Moieties Persoz Exam- Ketimine and Acetoacetate andin Hardness ple Functionality Functionality Ketimine (T = 3 h) 5 D1 B(Tetrafunctional) No 28 (Tetra- + functional) Polyester (AcAc) C 6 D1 B(Tetrafunctional) No 43 (Tetra- + functional) Polyacrylate (AcAc)D 7 D1B (Tetrafunctional) No 21 (Tetra- + functional) Epoxide F (Epon 1001) 8D1 Tetraacrylate E No 32 (Tetra- (Tetrafunctional) functional) +Polyester (AcAc) C 9 D1 Tetraacrylate E No 26 (Tetra- (Tetrafunctional)functional) + Polyacrylate (AcAc) D 10  D1 B (Tetrafunctional) No 42(Tetra- + functional) Isocyanate G (Tolonate HDT) 11  D1 B(Tetrafunctional No 35 (Tetra- + functional) Isocyanate G + (TolonateHDT) A (Difunctional) 12  D4 B No 80 (Trifunctional) (Tetrafunctional)13  D4 B No 50 (Trifunctional) (Tetrafunctional) + Polyacrylate (AcAc)D

Example 14

Tetraketimine (single reactor prep; FeCl₃ catalyst)

A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Ar inlet and outlet wascharged with diethylene triamine (47.25 g, 0.458 mol) and4-methyl-2-pentanone (122.25 g, 1.22 mol). The mixture was heated toreflux under Ar and water was removed azeotropically via the Dean-Starktrap. The reflux was continued until the reaction temperature reached142° C. The mixture was cooled to room temperature and 1,6-hexanedioldiacrylate (52.3 g, 0.229 mol) and the iron(III) chloride catalyst (1.25g) were then added to the reaction flask. The resulting mixture wasstirred under Ar at room temperature for 48 h and then filtered under Arto remove the catalyst.

Example 15

Tetraketimine (single reactor prep; Sc(CF₃SO₃), catalyst)

A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Ar inlet and outlet wascharged with diethylene triamine (47.25 g, 0.458 mol) and4-methyl-2-pentanone (122.25 g, 1.22 mol). The mixture was heated toreflux under Ar and water was removed azeotropically via the Dean-Starktrap. The reflux was continued until the reaction temperature reached142° C. The mixture was cooled to room temperature and 1,6-hexanedioldiacrylate (52.3 g, 0.229 mol) and Sc(CF₃SO₃)₃ catalyst (2.62 g) werethen added to the reaction flask. The resulting mixture was stirredunder Ar at room temperature for 48 h and then filtered under Ar toremove the catalyst.

Example 16

Tetraketimine (single reactor prep; 10 wt. % FeCl₃ on alumina catalyst)

A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Ar inlet and outlet wascharged with diethylene triamine (47.25 g, 0.458 mol) and4-methyl-2-pentanone (122.25 g, 1.22 mol). The mixture was heated toreflux under Ar and water was removed azeotropically via the Dean-Starktrap. The reflux was continued until the reaction temperature reached142° C. The mixture was cooled to room temperature and 1,6-hexanedioldiacrylate (52.3 g, 0.229 mol) and the iron(III) chloride catalyst (16g, 10 wt. % on alumina) were then added to the reaction flask. Theresulting mixture was stirred under Ar at room temperature for 48 h andthen filtered under Ar to remove the catalyst.

Example 17

Tetraketimine (single reactor prep; 5 wt. % FeCl₃ on silica catalyst)

A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Ar inlet and outlet wascharged with diethylene triamine (47.25 g, 0.458 mol) and4-methyl-2-pentanone (122.25 g, 1.22 mol). The mixture was heated toreflux under Ar and water was removed azeotropically via the Dean-Starktrap. The reflux was continued until the reaction temperature reached142° C. The mixture was cooled to room temperature and 1,6-hexanedioldiacrylate (52.3 g, 0.229 mol) and the iron(III) chloride catalyst (25g, 5 wt. % on silica) were then added to the reaction flask. Theresulting mixture was stirred under Ar at room temperature for 48 h andthen filtered under Ar to remove the catalyst.

Example 18

Hexaketimine (single reactor prep: 5 wt. % FeCl₃ on silica catalyst)

A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Ar inlet and outlet wascharged with diethylene triamine (47.25 g, 0.458 mol) and4-methyl-2-pentanone (122.25 g, 1.22 mol). The mixture was heated toreflux under Ar and water was removed azeotropically via the Dean-Starktrap. The reflux was continued until the reaction temperature reached142° C. The mixture was cooled to room temperature and trimethanolpropane triacrylate (45.24 g, 0.153 mol) and the iron(III) chloridecatalyst (25 g, 5 wt. % on silica) were added to the reaction flask. Theresulting mixture was stirred under Ar at room temperature for 48 h andthen filtered under Ar to remove the catalyst.

Example 19

Octaketimine (single reactor prep; 5 weight percent FeCl₃ on silicacatalyst)

A three neck flask equipped with a magnetic stirrer, Dean-Stark trap andcondenser, thermometer, oil heating bath and an Ar inlet and outlet wascharged with diethylene triamine (47.25 g, 0.458 mol) and4-methyl-2-pentanone (122.25 g, 1.22 mol). The mixture was heated toreflux under Ar and water was removed azeotropically via the Dean-Starktrap. The reflux was continued until the reaction temperature reached142° C. The mixture was cooled to room temperature and pentaerythritoltetraacrylate (40.34 g, 0.114 mol) and the iron(III) chloride catalyst(25 g, 5 wt. % on silica) were then added to the reaction flask. Theresulting mixture was stirred under Ar at room temperature for 48 h andthen filtered under Ar to remove the catalyst.

What is claimed is:
 1. A two-pack coating composition comprising acomponent (i) and a component (ii) wherein: (i) comprises from 10 to 90weight percent of an oligomer or a polymer having a weight averagemolecular weight not exceeding about 5,000 and functionality selectedfrom one or more of acetoacetate, acrylate, isocyanate, epoxide andcyclic carbonate moieties; and (ii) comprises from 10 to 90 weightpercent of an imine reactive diluent having a weight average molecularweight from about 100 to 50,000 that is substantially free ofhydrogen-bonding moieties and contains at least three imine groups permolecule wherein all percentages are based on the total weight of saidcomponents (i) and (ii).
 2. The coating composition of claim 1 whereinsaid component (i) further comprises a polymeric component (iii)selected from at least one of a polyacrylate, polyepoxide, polyurethaneand polyester, the component having a weight average molecular weightbetween about 5,000 to 100,000 and a pendant functionality selected fromthe group consisting of at least one of acetoacetate, acrylate, epoxide,isocyanate, or cyclic carbonate moieties, the functionality comprisingabout 10 to 90 percent based on the weight of the monomer; thecomposition comprising from about 50:1 to 1:2 by weight of saidcomponents (i+ii) to said component (iii).
 3. The coating composition ofclaim 1 where the ratio of ketimine to said acetoacetate, acrylate,epoxide, isocyanate, or cyclic carbonate moieties is in the range 5:1 to1:5.
 4. The coating composition of claim 2 wherein: said component (i)comprises from 25 to 75 weight percent of said oligomer or polymer; saidcomponent (ii) comprises from 25 to 75 weight percent of said iminereactive diluent; and said component (iii) comprises from 1 to 50 weightpercent of said polyester polyol or polyacrylic polyol.
 5. The coatingcomposition of claim 4 wherein: said oligomer or polymer of saidcomponent(i) is functionalized with acetoacetate moieties; said iminereactive diluent of said component (ii) is functionalized with ketiminemoieties; and said polyester polyol or polyacrylic polyol of saidcomponent (iii) is functionalized with acetoacetate moieties.
 6. Thetwo-pack coating composition of claim 1 or 2 wherein said imine reactivediluent is of the following formula:


7. A method for making the coating composition of claim 1 comprisingadmixing the components (i), and (ii).